The present invention relates generally to an internal combustion engine. The present invention also relates to a device and method for starting the internal combustion engine, and, more specifically, to an engine starting device that is capable of storing energy in an elastic member and then releasing the energy to start the engine. The present invention also relates to a device and method for stopping the internal combustion engine or, at least, for absorbing energy of the engine upon shutdown. The engine starting device is particularly adapted for use with small internal combustion engines such as those provided on power lawn mowers, generators, snow blowers, garden tractors, and other machinery.
Small internal combustion engines have been equipped with manually operable recoil starters which include a central shaft, a rope pulley rotatable about the central shaft, retractable clutches or dogs connected to the rope pulley and a starter rope wrapped around the rope pulley. The starter rope may be pulled to rotate the rope pulley in a starting direction, such that the dogs engage the flywheel, and the flywheel and the crankshaft are also rotated in a starting direction. The engine is then driven through a number of revolutions sufficient for starting.
Although recoil starters of the type described above are commonly used with small internal combustion engines, there are certain disadvantages inherent in their operation. For example, the operator must possess a sufficient amount of strength and manual dexterity to pull the starter rope to rotate the flywheel and crankshaft. Under some conditions, the operator may have to pull the starter rope several times before the engine is successfully started. For some operators, this is a mere inconvenience. For other operators, including the elderly and the physically challenged, pulling a starter rope multiple times may present a difficult task.
An alternative to recoil starters and other manual starters are automatic starters which include a battery-powered electric motor for driving the flywheel through initial starting revolutions. Such a starter may be actuated by merely activating an electrical switch in the form of a push button or key device. Although this concept provides an engine starting device that is both easy to operate and generally effective, the electric motor, the battery used to power the motor, and associated components can add weight and cost to an engine. For small internal combustion engines such as those intended for use with lawn mowers, generators, and like machines, adding even a small amount of weight and cost to the engine can negatively impact the market competitiveness of the engine and/or the machine.
Another type of automatic starter is an engine starting device that utilizes stored energy in a spring to rotate the crankshaft and to start the engine. In these engine starting devices a mechanism must be provided to wind the spring. For example, U.S. Pat. No. 1,936,554, which is assigned to Briggs and Stratton Corporation (the assignee of the present invention) discloses an electric motor that is positioned adjacent the spring and which may be operated to wind the spring. It is also known to provide a manual crank mechanism interconnected with the spring and operable to wind the spring. Further, it is known to provide a winding mechanism interconnected with the crankshaft that is operable to wind the spring during normal engine running conditions.